As the method for separating and purifying an amino acid produced by fermentation from a culture, a method in which a culture of which solid components such as microbial cells have been removed by centrifugation, condensing precipitation using a polymeric condensing precipitator or ultrafiltration and the like is charged onto an ion exchange resin to allow an amino acid to be adsorbed on the resin and then the amino acid is eluted is known (Patent Reference 1), and it is essential for this method to involve pretreatment for removing the microbial cells from the culture before the culture is brought into contact with the ion exchange resin.
The method in which a culture containing microbial cells is charged onto the top of a column filled with an ion exchange resin to allow an amino acid to be adsorbed on the resin and then water is poured into the column via the bottom thereof to allow the cells to be deposited on the resin, to float up and to be removed via the top of the column and then the amino acid is eluted is also known (Patent Reference 2), and it has a disadvantageously poor amino acid purification efficiency since most of the cells contained in the culture together with the amino acid is deposited on the resin.    Patent Reference 1: Japanese Published Examined Patent Application No. 5050/1964    Patent Reference 2: Japanese Published Examined Patent Application No. 53509/1992